update to rails 4.1
remove Digest deprecation warning
switch to minitest from test/unit

not sure if this is the right change, but tests seem to run
fix failing tests

not sure if the to_a fixes to get collections from activerecord is the right way
remove assert which should not be used for cucumber.
fix running minimal test framework using minitest
activerecord associations do not act like a collection anymore, so convert to array first 
before using map, collect, etc.
add missing images

these were never there. used in mobile project view
try another day to get rid of test failure

I do not see the failure locally, guessing this causes the failure...
Merge pull request #218 from TracksApp/rails41

Rails 4.1 migration